The ETT differs from the standard configuration in that the
struts are one-half
length and an intermediate ring is added which provides rigidity
and stability to the assembly. For example, instead of
using 3 60-inch struts in the telescope design, the ETT incorporates
six 30-inch struts. An Easy Transport Telescope!

In
the smaller sizes, 8" and 10" Newtonians, these
telescopes will break down to a size suitable for airline
transport as baggage. The larger telescopes don't meet that
requirement, but still make the telescope much easier to
transport, setup and store.

This example is a 12.5"
Transportable Telescope made for George in Show Low Arizona.
George sent me his mirror and mirror cell, spider/secondary and
focuser. He had a pair of finder rings to be mounted as well.

The overall length of the struts are 59.5" long
and the eyepiece stands at 64.5" when pointed at the zenith.
Each section of the struts is 29 1/4". The intermediate ring is
.5" thick and is also made of furniture grade Baltic birch.

The footprint of the rocker box is 19"x21.5" and stands 16" all.
The height of rocker box can vary. In this case, since George
had a fairly heavy finder and a 1.5# eyepiece, I've put the
altitude bearings a little higher on the OTA. A sliding
counterweight will assist in the final balance of the telescope,
when needed.

The scope was built and
delivered in December 2008.

The 12.5" telescope from the
rear. Here is the removable dew shield is installed. In this
case, the mirror cell is a Kenneth Novak. I modified the cell,
slightly, to allow a larger center opening to assist is
cool-down of the mirror.

12.5" F5.16 ETT as seen from
the front. The focuser baffle is in place. The entire telescope
assembles and disassembles without the need for tools.

The ETT with the dew shield
removed. The mirror cover is standard equipment and is in place
whether the dew shield is installed or removed.

Another view with the dew
shield in place.

Since the "travel struts"
are 1/2-length, it is easy to use the bottom half of the strut
when transporting the telescope. Here, the altitude bearings are
left in place. The one-half strut length is 29 1/4".

Simply remove the altitude
bearings and nest the OTA assembly in the rocker box. The
intermediate ring is at the bottom of the rocker box.

The assembly is just about
complete. The sliding counterweight and finder rings are
installed. I include a "finder" clamp regardless of the finder
type. Many amateurs use a small, lightweight, red-dot zero-power
finder.

The intermediate ring and
focuser baffle fit nicely into the bottom of the rocker box for
easy transport.